With the rapidly spreading deployment of mass data handling devices, such as video and image handling devices, reliable storage of huge amounts of data is required, for direct storage or as part of backup storage. As more and more devices are provided with network connectivity, distributed storage of data in network connected devices is considered as a cost effective solution. In such distributed data storage systems, to ensure data availability and resilience to temporary or permanent data loss, methods have been developed that copy a same item of data to multiple network connected devices in the distributed data storage network. This is called data replication. Data replication has to be taken in a broad sense, and covers mere data duplication as well as usage of coding techniques such as erasure or regenerating codes. To cope with the risk of permanent or temporary data loss due to device failure or device unavailability, a high replication factor (i.e. a high number of copies) is wished. However, to reduce costs in terms of communication and storage size needed (so-called replication costs) it is wished to have a low replication factor.
What is needed is a solution that achieves high level of data availability of distributed data storage that jointly considers resilience to data loss and replication costs.